Text of AP Biology 2007-2008 Prokaryotes Domain Bacteria Domain Archaebacteria Domain Bacteria Domain...
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AP Biology 2007-2008 Prokaryotes Domain Bacteria Domain
Archaebacteria Domain Bacteria Domain Archaea Domain Eukarya Common
ancestor
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What characteristics make Archaea more like eukaryotes than
prokaryotes? No peptidoglycan in cell wall More than 1 RNA
polymerase Some introns Met is 1 st amino acid in protein synthesis
Ribosomes more like eukarytoes (Streptomycin does not kill archaea)
Domain Bacteria Domain Archaea Domain Eukarya Common ancestor
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Bacteria live EVERYWHERE! Bacteria live in all ecosystems on
plants & animals in plants & animals in the soil in depths
of the oceans in extreme cold in extreme hot in extreme salt on the
living on the dead Microbes always find a way to make a
living!
Prokaryote vs. Eukaryote Chromosome double helix Prokaryote
Eukaryote
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Genetic variation in bacteria Mutations bacteria can reproduce
every 20 minutes binary fission error rate in copying DNA 1 in
every 200 bacteria has a mutation you have billions of E. coli in
your gut! lots of mutation potential! Genetic recombination
bacteria swap genes small supplemental circles of DNA direct
transfer of DNA conjugation
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Metabolic Relation to Oxygen How are bacteria categorized by
the effect that oxygen has on growth? Obligate aerobes Facultative
anaerobes Obligate anaerobes What role do prokaryotes play in
nitrogen cycling? Only way that nitrogen gas can be incorporated
into organic molecules
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Variations in Cell Interior internal membranes for
photosynthesis like a chloroplast (thylakoids) internal membranes
for respiration like a mitochondrion (cristae) aerobic bacterium
mitochondria cyanobacterium (photosythetic) bacterium
chloroplast
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Origins of Metabolic Diversity Heterotrophs most likely came
before photoautotrophs (parsimony) Glycolysis was probably the
first metabolic pathway Natural selection favored autotrophs as
heterotrophs depleted food supply Cyanobacteria introduce chl a and
oxygen gas.
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Cell Wall What are the functions of the cell wall in
prokaryotes? Maintain cell shape Protection Prevent bursting in
hypotonic environment Made of peptidoglycan Why is some food
preserved by salting it? Hypertonic environment plasmolyzes
bacterial cells
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Prokaryote Cell Wall Structure peptide side chains cell wall
peptidoglycan plasma membrane protein Gram-positive bacteria
Gram-negative bacteria peptidoglycan plasma membrane outer membrane
outer membrane of lipopolysaccharides cell wall peptidoglycan =
polysaccharides + amino acid chains lipopolysaccharides = lipids +
polysaccharides Thats important for your doctor to know!
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Prokaryotic metabolism How do bacteria acquire their energy
& nutrients? photoautotrophs photosynthetic bacteria
chemoautotrophs oxidize inorganic compounds nitrogen, sulfur,
hydrogen heterotrophs live on plant & animal matter decomposers
& pathogens
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Disease Disease exotoxins release poisons such as botulism and
cholera Endotoxins seen in outer membrane of gram neg. bacteria
(Salmonella) What are Kochs postulates and why are they important?
Kochs postulates used to isolate pathogen causing disease
Bacteria as beneficial (& necessary) Life on Earth is
dependent on bacteria recycling of nutrients from dead to living
only organisms that can fix N from atmosphere needed for synthesis
of proteins & nucleic acids plant root nodules help in
digestion (E. coli) digest cellulose for herbivores cellulase
enzyme produce vitamins K & B 12 for humans produce foods &
medicines from yogurt to insulin
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Germinating akinetes
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AP Biology 2007-2008 Got any Questions?? Ask da Boss!
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Are these bacteria Gram + or Gram ? Gram positive Gram
negative
